Improvement in blast-furnace breast-plate



B. A. FISHER.

Blast-Furnace Breast-Plates.

N 141,043, Patentedjuly 22,1873.

Witnesses AM P110 lD-LIFIOGRAPIIIL 00. N x(bsaomvsfs Pnqcass.)

arch to the slag-spouts.

UNITED STATES PATENT OEEIcE.

ROBERT A. FISHER, OF SAN FRANCISCO, CALIFORNIA.

. IMPROV EMENT IN BLAST-FURNACE BREAST-PLATE.

Specification forming part of Letters Patent No. 141,043, dated July 22, 1873 application filed June 6,1873.

To all whom it may concern Be it known that I, ROBERT A. FISHER, of San Francisco city and county, State of California, have invented an Improved Front for Smelting-Furnaces; and I do hereby declare the following description and accompanying drawings are sufficient to enable any person skilled in the art or science to which it most nearly appertains to make and use my said invention or improvement without further invention or experiment.

In some styles of blastfurnaces the metallic spout through which the fluid slag and mat run from the furnace are attached to a metallic front technically called a breast-plate. The front or breast plate in common use is simply a plate of rolled or cast iron, a horizontal section of which is a straight line. The breastplate is held in position by bolts or side plates extending from the front to the back of the furnace. The slag and that produced during the smelting process, near the small end of the tuyeres, flow from thence under the fire- Unless maintained at a sufliciently-high temperature the slag and mat in their passage to the slag-spouts thicken, and sometimes chill or become solid. In order to keep the slag sufficiently hot to run easily it is necessary to maintain a heap of burning fuel within the walls of the furnace from the line of the fire-arch g g to the breast-plate B B. The amount of fuel required for this purpose in a large furnace is very great. Besides this disadvantage in the breast-plate in common use there is also this disadvantage, that in the reduction of certain classes'of ore the breast-plate is rapidly corroded and eaten away if, by chance, it becomes exposed to the direct action of the slag and mat.

My improvements consist, first, in constructin g the front or breast plate A of the furnace with an angular indentation, as shown at Fig. 1, so as to carry that portion of the front in which the slag-spouts G are secured almost up to the fire-arch, thereby shortening the distance which the slag has to flow between the tuyere and slag-spouts, and largely reducing the amount of fuel required to prevent the slag and mat from becoming chilled after passing under the fire-arch.

To prevent the destruction of that portion of the breast-plate on which the slag-spouts are secured, I attach, by rivets or otherwise, a shield or back, D, of wrought or cast iron, or itsequivalent, inside of the usual front, and fill the space 0 intervening between the usual front and this shield with fire-clay or other fire-resisting or refractory material, so that in case the shield or supplementary back piece D should become destroyed by corrosion a new one can be readily supplied in its place in a short time, and with very little trouble, as soon as the furnace is out of blast.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

J. The arrangement of the slag-spouts in I the front of the furnace, as described, so that they shall be heated from the fire-arch, pre- In witness whereof I hereunto set my hand and seal.

ROBERT A. FISHER.

Witnesses JOHN LKBOONE, G. M. RICHARDSON. 

